FB2020_05, released Oct 14, 2020
Gene: Dmel\en
FB2020_05, released Oct 14, 2020
Gene: Dmel\en
Gene: Dmel\en
Gene: Dmel\en
Eng, en1, spermatheca, spt
transcription factor - homeodomain - engrailed class - segment polarity gene - involved in compartment identity and boundary formation - positively regulates the and negatively regulates the Hedgehog targets and
Please see the JBrowse view of Dmel\en for information on other features
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Gene model reviewed during 5.49
3.6, 2.7, 1.4 (northern blot)
en protein is used as a marker for the embryonic dorsal large intestine.
Polyclonal antibody is to the entire en protein.
Phosphorylated. Phosphorylation may directly or allosterically modify its function.
Click to get a list of regulatory features (enhancers, TFBS, etc.) and gene disruptions (point mutations, indels, etc.) within or overlapping Dmel\en using the Feature Mapper tool.
Comment: anlage in statu nascendi
Comment: anlage in statu nascendi
Comment: anlage in statu nascendi
Comment: anlage in statu nascendi
Comment: anlage in statu nascendi
Comment: reported as procephalic ectoderm anlage
Comment: reported as procephalic ectoderm anlage
Comment: reported as procephalic ectoderm anlage
Comment: reported as procephalic ectoderm anlage
Comment: reported as ventral nerve cord anlage
Comment: reported as procephalic ectoderm primordium
Comment: reported as procephalic ectoderm primordium
Comment: reported as procephalic ectoderm primordium
Comment: reported as procephalic ectoderm primordium
Comment: reported as procephalic ectoderm primordium
Comment: reported as procephalic ectoderm primordium
Comment: reported as head epidermis primordium
Comment: reported as head epidermis primordium
Comment: reported as head epidermis primordium
Comment: reference states 3-12 hr AEL
en is expressed in posterior midline glia but not in anterior midline glia in stage 12 embryos. After its early pair rule and segment polarity expression patterns in early embryos, en expression becomes more expansive. At stage 10, en expression along with run expression divides the midline into four regions, anterior (runt[+], en[-]), middle (runt[-], en[-]), posterior (runt[-], en[+]), and extreme posterior (runt[-], en[-]). At stage 10, en is expressed in 2 midline cells. A second, late phase of en expression was activated in the extreme posterior runt[-] en[-] cells that, in combination with the early en[+] cells, generated a single posterior en[+] region containing around eight cells. By the end of stage 11, en is expressed in all posterior midline glia. These en[+] cells give rise to the posterior midline glia, MP4-6, and the median neuroblast.
Expression pattern inferred from unspecified enhancer trap line.
Comment: expressed in one dorsal multidendritic neuron per segment
Comment: rows G,H
en protein is expressed at similar levels in wing and haltere discs.
The en protein is localized to the nucleus, but becomes diffuse during mitosis.
en protein is expressed in a two cell wide row of cells anterior to the segment boundaries of each segment. Expression in the posterior row of cells decreases as a groove forms at the segment boundary.
The en protein is expressed in a specified subset of neuroblasts in embryonic stages 8-11. (see also FBrf 42042)
en expression was observed sequentially in 5 "centers" anterior to the mandibular segment starting at embryonic stage 8. These are the "en antennal stripe", the "en head spot", the "en intercalary spot", the "en expression in the anterior dorsal hemispheres" and the "en expression in the clypeolabrum". Later two of the spots split, generating the "en antennal spot" and the "en secondary head spot". The migration of these en-expressing cells was followed throughout embryonic development.
The en protein is expressed in the posterior half of each segment.
Comment: parasegment six, and posterior
GBrowse - Visual display of RNA-Seq signals
View Dmel\en in GBrowse 2
2-64
2-64
2-64.9
2-64.0
2-62.0
Please Note FlyBase no longer curates genomic clone accessions so this list may not be complete
Please Note This section lists cDNAs and ESTs that fall within the genomic extent of the gene model, which may include cDNAs and ESTs of genes within introns, or of overlapping genes. Please see GBrowse for alignment of the cDNAs and ESTs to the gene model.
For each fully sequenced cDNA the DGRC maintains various forms of the cDNA (e.g tagged or untagged) in several different host vectors for subsequent cloning and expression in Drosophila and Drosophila cell lines.
monoclonal
polyclonal antibody
monoclonal antibody
polyclonal
DNA-protein interactions: genome-wide binding profile assayed for en protein in 0-12 hr embryos; see mE1_TFBS_en collection report.
A 139bp minimal pairing sensitive element (PSE) from en regulatory DNA has been defined. This element mediates Pairing Sensitive Silencing (PSS). The PSE includes 8 protein binding sites at least 5 of which are important for pairing sensitive silencing. One of these is for pho protein, and another has the GAGAG sequence known to be bound by Trl and psq proteins.
Three EMS induced en alleles were identified in a screen for mutations affecting commissure formation in the CNS of the embryo.
When en is removed from Posterior cells, they transform into the Anterior cells of the same parasegment, rather than Anterior cells of the same segment.
In the developing abdomen the state of en, whether off or on, determines whether a cell is of Anterior or Posterior type. en acts in the Anterior compartment, where it is induced by hh gene product, in a narrow band of cells, which has crossed the Anterior/Posterior compartment boundary. en causes these cells to form a special type of cuticle.
Cell affinities in the adult abdomen depend on en : cells of the P compartment have affinities that are distinct from A cells.
Interactions between en and polyhomeotic are required to maintain the anterior-posterior boundary and posterior cell fate in the wing.
Segment polarity gene expression is necessary for the survival of specific rows of epidermal cells.
en promotes the development of the dorsolateral fat body, midgut visceral mesoderm and somatic gonads while it suppresses development of somatic muscles, heart and ventral fat body. There is a balance between fat body and somatic gonadal precursor (SGP) development with tin, wg and en driving cells in the primary clusters towards SGP development and srp driving them towards fat body development.
Genes known to be expressed in compartment-specific manner in discs are expressed in analogous patterns in each primordia.
en is one of a class of genes with TATA-less promoters that have the conserved DPE sequence.
Amino acids in the N-terminal arm of the homeodomain, as well as at position 54 of the homeodomain, control the DNA binding specificity of the homeodomain.
Despite the absence of a syncytium in C.floridanum embryos monoclonal antibodies to en, Ubx and abd-A demonstrate their cognate proteins are expressed in a conserved pattern in the post-gastrulation stages of development. The expression of the eve cognate protein is not completely conserved and lacks a pair rule phase to its expression.
Elevated en expression does not disrupt eye morphogenesis.
en is post-translationally modified by casein kinase II (CK-II). The targets for CK-II phosphorylation in vitro are serine residues 394, 397, 401 and 402, and phosphorylation by CK-II stimulates DNA binding.
Maintenance but not initiation of en gene expression in the embryo requires trx, which is also required to maintain stable long-term expression of the homeotic genes throughout development. trx is required for normal en expression in the wing imaginal disc. trx-dependent loss of en expression in the dorsal fat body is correlated with female sterility.
The organisation of the tail region of the embryo is documented from studies of cuticular markers enabling a more direct comparison between homologous structures on the embryo and larval cuticle.
en is involved in regulation of serotonin cell development.
Clonal analysis supports the view that dpp is a direct target of repression by en, and that en defines the posterior extent of the dpp stripe in the wing imaginal disc. The en-hh-ptc regulatory loop that is responsible for segmental expression of wg in the embryo is reused in imaginal disks to create a stripe of dpp expression along the A/P compartment boundary.
en both directs the posterior compartment pathway and creates the compartment border in wing development.
en governs growth and patterning in both anterior and posterior wing compartments by controlling the expression of the hh and dpp products as well as the response of the cells to them. en activity programs wing cells to express hh whereas the absence of en activity programs them to respond to hh by expressing dpp. Consequently, posterior cells secrete hh product and induce a stripe of neighboring anterior cells across the compartment boundary to secrete dpp.
Comparisons of early development to that in other insects have revealed conservation of some aspects of development, as well as differences that may explain variations in early patterning events.
Wild type activity of five segment polarity genes, wg, ptc, en, nkd and hh, can account for most of the ventral pattern elements in the embryo. wg is required for naked cuticle. wg generates the diversity of cell types within the segment but each specific cell identity depends on the activity of ptc, en, nkd and hh.
en is a specific repressor of activated transcription, and may act via a different mechanism than eve, perhaps by interfering with interactions between transcriptional activators and the general transcription machinery. A minimum repression domain of 55 residues, rich in alanine, can function when fused to a heterologous DNA binding domain. Unlike the repression domains of eve and Kr, the en repression domain is moderately charged.
The positioning of en stripes in the embryo is largely determined by the actions of negative regulators: run is required to limit the domains of en-expression in odd-numbered parasegments, while odd is required to limit the domains of en-expression in even-numbered parasegments. Activation of en at the anterior margins of the parasegments requires repression of run and odd by eve.
Choice of cell fate made by en expressing cells in embryonic parasegments is mediated by wg, in a function distinct from its early role in maintaining en expression. en expressing cells respond differently to wg at different stages of development:early wg stabilizes the subdivision of the body axis by maintaining en expression, whereas later input generates cell-type diversity.
en alleles fall into four classes, all recessive. Class 1: en1 (See en1 allele record for full description). Viable hemizygous and homozygous; fertile. Longitudinal cleft extends from rear border of scutellum forward, may be reduced to median nick or posterior flattening of scutellum. Wings larger, broader and thin textured with spatulate end; venation and distribution of sensilla abnormal in posterior wing compartment. Variable duplication of anterior triple row bristles on posterior margin; alula reduced, with costal-like bristles. Clones of en1 cells of posterior compartment origin fail to respect anterior-posterior compartment border in wing disc as do mwh1 clones in wing discs of en1 homozygotes. en1 abnormalities are associated with posterior compartment structures only, except for scutellar cleft. Not suppressed by su(Hw)1. Class 2: Lethal alleles with normal cytology. Embryonic lethal. Anterior margin of each segment defective. Pair rule defects in naked cuticle of T1, T3, A2, A4, A6, A8 result in pair-wise fusion of adjacent segments. Autonomous effects in adult cuticular clones observed in posterior compartment of proboscis, thorax, abdomen and genitalia. The en1/"enlethal" heterozygote characterized by wing abnormalities only; disruption of anterior crossvein, gap in vein IV and occasional socketted bristles on posterior margin. Class 3: Deficiencies and lethal alleles with inversion or translocation breakpoints. Embryonic lethal. Embryonic segment defects slight and variable. Alleles of this class in heterozygous combination witn en1 produce adults more extreme than en1. For example, in en1/en2, legs are truncated, the tarsi reduced to densely bristled stumps; wings are greatly enlarged and spatulate with greater disruption of veins IV and V; higher penetrance of socketed bristles along the posterior margin. Extreme scutellar cleft. Class 4: Non-lethal alleles with breakpoints. Hemizygous viable, embryos normal. Heterozygous with other allele classes, variable gaps in wing veins IV and V. Variable reductions or deletions in male and female genitalia. Scutellum may also be affected.
Embryos mutant for two or more Pc-group genes (Pc, Scm, Pcl, Psc, Asx, E(Pc), E(z), ph-d, pho and esc) show strong ectopic en expression, but only weak derepression occurs if embryo is mutant at only one of the Pc group genes. This effect is independent of the function of en itself, and wg. Expression of en in esc mutant embryos is almost normal, suggesting that esc may function in a pathway different from the other genes in the group.
en expression pattern in the embryonic head strengthens the hypothesis that the clypeolabrum evolved from the fusion of paired labral appendages.
In transfection assays en is an active transcriptional repressor. Active repression is distinct from the effects of passive homeodomain-containing proteins which repress when competing with activators for binding sites and activate when competing with en. Active repression activity maps outside the en homeodomain and this activity can be transferred to a heterologous DNA binding domain.
When a fragment of en DNA extending from -2.4kb to +0.8kb is included in the CaSpeR vector the eye colour of transformants often behaves anomalously, half of the homozygotes have a lighter eye colour than the heterozygotes and a quarter have the same eye colour as the heterozygotes. This occurred at many different insertion sites whether the upstream en fragment is directly adjacent to w+mC or when it is 1kb away. The suppression of eye colour is dependent on the proximity of the two copies of the transposon, either in cis or trans. The protein that mediates this phenomenon is probably not a homeodomain-containing protein as deletion of the homeodomain binding sites results in suppression of w expression.
Mutations in zygotic polarity gene en do not interact with RpII140wimp.
en mutants exhibit variable pair rule fusions and segment polarity reversals.
en intron 1 works as a stripe specific enhancer.
The crystal structure of a complex containing the en homeodomain and a duplex DNA site has been determined.
The en1/"enlethal" heterozygote characterized by wing abnormalities only; in some combinations complementation is complete or nearly so.
A transient expression assay has been employed to investigate the potential of homeobox genes to function as transcriptional activators.
The expression of en protein in Drosophila, grasshopper and crayfish has been compared.
Genetic analysis demonstrates that en is dispensable for efficient homeotic gene expression in the visceral mesoderm.
Striped en expression during post-blastoderm development is controlled by a cis-regulatory programme distinct from that controlling the establishment of expression at the cellular blastoderm stage.
en protein isolated from cultured cells and embryos is post-translationally modified.
Heat shock induced en gene expression causes pattern defects similar to those in embryos lacking en gene product. The sensitivity to heat shock is only during the cellular blastoderm and early gastrulation periods when the en protein localises into segmentally reiterated stripes and represents only a small portion of the normal period of en gene expression.
en is expressed in the posterior (but not the anterior) compartments of the embryo and larva.
en mutant genital discs show reductions or deletions.
"enlethal" alleles show no maternal effect.
At 29oC, duplication of anterior compartment bristles in mirror-image symmetry in the posterior compartment of second antennal segment occurs.
"enlethal" clones are without effect in anterior compartments and in eye-antennal region.
The gene is named "engrailed", a heraldic term from the middle-age french "engraile", literally "dented by hail", after the mutant phenotype of a notch in the scutellum.
